Superconducting switches for modular quantum networks

Josephson-junction-based superconducting circuits enable coherent controls of microwave signals at cryogenic temperatures, providing a foundation for modular quantum networks. This talk presents superconducting microwave switches that provide rapid, low-loss, and scalable routing of microwave signals, establishing a versatile building block for modular quantum networks. We propose a quantum network architecture that integrates a Tunable Inductor Bridge (TIB) as the switch, a seam-free 2D–3D interface that couples the TIB to high-Q cavities, and a current-controlled TIB that implements a persistent-current switch to realize a "set-and-forget" control. Our switch achieves a broadband 20-dB on/off ratio, 200 pW power handling, and 600 MHz modulation bandwidth. Combining the TIB with the 2D-3D interface, we show designs and preliminary results of a small two-module quantum network.